Print engine assembly with dual motor assemblies

ABSTRACT

A print engine for in an inkjet printer includes a chassis; a print cartridge mounted to the chassis, the print cartridge including a wound length of print media and defining therewithin a plurality of ink reservoirs; a first motor assembly mounted to the chassis, the first motor assembly driving a roller of the print cartridge to transport the print media; a printhead assembly engaged with the print cartridge, the printhead assembly ejecting ink from the reservoirs onto the transported print media; a cutter assembly for cutting a printed length of print media from the remaining wound length; a second motor assembly mounted to the chassis, the second motor assembly driving the cutter assembly; and a capping mechanism displaceable towards and away from the printhead by a displacement mechanism, the capping mechanism including a carrier having an elongate rib positioned to abut with the printhead.

CROSS-REFERENCE TO RELATED APPLICATION

This Application is a Continuation of U.S. application Ser. No.12/246,436 filed Oct. 6, 2008, which is a Continuation Application ofU.S. Ser. No. 10/920,284 filed on Aug. 18, 2004, now Issued U.S. Pat.No. 7,448,746, which is a Continuation Application of U.S. Ser. No.10/040,472 filed on Jan. 9, 2002, now Issued U.S. Pat. No. 6,942,334 allof which are herein incorporated by reference.

BACKGROUND OF THE INVENTION

The following invention relates to a hand-held computing device, of thetype commonly referred to as a personal digital assistant, with aninternal printer. More particularly, though not exclusively, theinvention relates to a personal digital assistant having a pagewidthdrop-on-demand printhead and a source of print media located in thepersonal digital assistant.

A personal digital assistant, such as the type commonly known under thetrade mark Palm Pilot, is typically a hand-held portable electronicdevice having a fold down display screen and a control panel. Thedisplay screen is typically of a touch screen type that reacts totouches made by a user controlling a pixel pen. Alternatively userinputs are provided to the digital assistant through a keypad orin-built curser ball.

Personal digital assistants provide a user with the convenience to beable to store diaries, address books, meeting schedules etc in acompact, transportable form as well as to be able to instantly add newentries such as meeting notes, new addresses etc.

Much of the benefit of such portable prior art personal digitalassistants is lost however if a print-out of any stored information isrequired. To print information, prior art digital assistants must beconnected to a print device compatible with the digital assistant whichrequires additional cabling to be carried thus reducing the portabilityof the digital assistant. Alternatively the digital storage medium thatstores the images within the digital assistant must be transferred toanother computer having compatible software for reading the storagemedium and which is connected to a printer. Each of the abovealternatives can only be implemented if these other computing devicesare readily at hand. The prior art personal digital assistants are thusyet to reach their maximum potential as a functional medium for storingand transporting information. With the advent of mobile communicationstechnologies potentially allowing electronic commerce to be conductedthrough one's digital assistant, it is becoming essential that digitalassistants have more suitable print capabilities for printing hardcopies of the information stored in the digital assistant.

However, presently, printer technology has not been suitable forincorporating into personal digital assistants without a significantcompromise in the size and portability of such devices.

SUMMARY

A print engine for in an inkjet printer comprises a chassis; a printcartridge mounted to the chassis, the print cartridge including a woundlength of print media and defining therewithin a plurality of inkreservoirs; a first motor assembly mounted to the chassis, the firstmotor assembly driving a roller of the print cartridge to transport theprint media; a printhead assembly engaged with the print cartridge, theprinthead assembly ejecting ink from the reservoirs onto the transportedprint media; a cutter assembly for cutting a printed length of printmedia from the remaining wound length; a second motor assembly mountedto the chassis, the second motor assembly driving the cutter assembly;and a capping mechanism displaceable towards and away from the printheadby a displacement mechanism, the capping mechanism including a carrierhaving an elongate rib positioned to abut with the printhead.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of example with reference tothe accompanying diagrammatic drawings in which:

FIG. 1 shows a three dimensional view of a print engine, includingcomponents in accordance with the invention;

FIG. 2 shows a three dimensional, exploded view of the print engine;

FIG. 3 shows a three dimensional view of the print engine with aremovable print cartridge used with the print engine removed;

FIG. 4 shows a three dimensional, rear view of the print engine with theprint cartridge shown in dotted lines;

FIG. 5 shows a three dimensional, sectional view of the print engine;

FIG. 6 shows a three dimensional, exploded view of a printheadsub-assembly of the print engine;

FIG. 7 shows a partly cutaway view of the printhead sub-assembly;

FIG. 8 shows a sectional end view of the printhead sub-assembly with acapping mechanism in a capping position;

FIG. 9 shows the printhead sub-assembly with the capping mechanism inits uncapped position;

FIG. 10 shows an exploded, three dimensional view of an air supplyarrangement of the print engine;

FIG. 11 shows a personal digital assistant having a built in printer;

FIG. 12 shows the internal components of a personal digital assistanthaving a built in printer;

FIG. 13 shows a personal digital assistant with a releasable coverportion; and

FIG. 14 is a schematic block diagram of components incorporated into apersonal digital assistant having a built-in printer.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In FIGS. 1 to 10 of the accompanying drawings, reference numeral 500generally designates a print engine, in accordance with the invention.The print engine 500 includes a print engine assembly 502 on which aprint roll cartridge 504 is removably mountable. The print cartridge 504is described in greater detail in our co-pending applications U.S. Ser.No. 09/607,993 and U.S. Ser. No. 09/607,251, the contents of thatdisclosure being specifically incorporated herein by reference.

The print engine assembly 502 comprises a first sub-assembly 506 and asecond, printhead sub-assembly 508.

The sub-assembly 506 includes a chassis 510. The chassis 510 comprises afirst molding 512 in which ink supply channels 514 are molded. The inksupply channels 514 supply inks from the print cartridge 504 to aprinthead 516 (FIGS. 5 to 7) of the printhead sub-assembly 508. Theprinthead 516 prints in four colors or three colors plus ink which isvisible in the infra-red light spectrum only (hereinafter referred to as‘infra-red ink’). Accordingly, four ink supply channels 514 are definedin the molding 512 together with an air supply channel 518. The airsupply channel 518 supplies air to the printhead 516 to inhibit thebuild up of foreign particles on a nozzle guard of the printhead 516.

The chassis 510 further includes a cover molding 520. The cover molding520 supports a pump 522 thereon. The pump 522 is a suction pump, whichdraws air through an air filter in the print cartridge 504 via an airinlet pin 524 and an air inlet opening 526. Air is expelled through anoutlet opening 528 into the air supply channel 518 of the chassis 510.

The chassis 510 further supports a first drive motor in the form of astepper motor 530. The stepper motor 530 drives the pump 522 via a firstgear train 532. The stepper motor 530 is also connected to a driveroller 534 (FIG. 5) of a roller assembly 536 of the print cartridge 504via a second gear train 538. The gear train 538 engages an engageableelement 540 (FIG. 2) carried at an end of the drive roller 534. Thestepper motor 530 thus controls the feed of print media 542 to theprinthead 516 of the sub-assembly 508 to enable an image to be printedon the print media 542 as it passes beneath the printhead 516. It alsoto be noted that, as the stepper motor 530 is only operated to advancethe print media 542, the pump 522 is only operational to blow air overthe printhead 516 when printing takes place on the print media 542.

The molding 512 of the chassis 510 also supports a plurality of inksupply conduits in the form of pins 544 which are in communication withthe ink supply channels 514. The ink supply pins 544 are receivedthrough an elastomeric collar assembly 546 of the print cartridge 504for drawing ink from ink chambers or reservoirs 548 (FIG. 5) in theprint cartridge 504 to be supplied to the printhead 516.

A second motor 550, which is a DC motor, is supported on the covermolding 520 of the chassis 510 via clips 552. The motor 550 is providedto drive a separating means in the form of a cutter arm assembly 554 topart a piece of the print media 542, after an image has been printedthereon, from a remainder of the print media. The motor 550 carries abeveled gear 556 on an output shaft thereof. The beveled gear 556 mesheswith a beveled gear 558 carried on a worm gear 560 of the cutterassembly 554. The worm gear 560 is rotatably supported via bearings 562in a chassis base plate 564 of the printhead sub-assembly 508.

The cutter assembly 554 includes a cutter wheel 566, which is supportedon a resiliently flexible arm 568 on a mounting block 570. The worm gear560 passes through the mounting block 570 such that, when the worm gear560 is rotated, the mounting block 570 and the cutter wheel 566 traversethe chassis base plate 564. The mounting block 570 bears against a lip572 of the base plate 564 to inhibit rotation of the mounting block 570relative to the worm gear 560. Further, to effect cutting of the printmedia 542, the cutter wheel 566 bears against an upper housing or capportion 574 of the printhead sub-assembly 508. This cap portion 574 is ametal portion. Hence, as the cutter wheel 566 traverses the cappedportion 574, a scissors-like cutting action is imparted to the printmedia to separate that part of the print media 542 on which the imagehas been printed.

The sub-assembly 506 includes an ejector mechanism 576. The ejectormechanism 576 is carried on the chassis 510 and has a collar 578 havingclips 580, which clip and affix the ejector mechanism 576 to the chassis510. The collar 578 supports an insert 582 of an elastomeric materialtherein. The elastomeric insert 582 defines a plurality of openings 584.The openings 584 close off inlet openings of the pins 544 to inhibit theingress of foreign particles into the pins 544 and, in so doing, intothe channels 514 and the printhead 516. In addition, the insert 584defines a land or platform 586 which closes off an inlet opening of theair inlet pin 524 for the same purposes.

A coil spring 588 is arranged between the chassis 510 and the collar 578to urge the collar 578 to a spaced position relative to the chassis 510when the cartridge 504 is removed from the print engine 500, as shown ingreater detail in FIG. 3 of the drawings. The ejector mechanism 576 isshown in its retracted position in FIG. 4 of the drawings.

The printhead sub-assembly 508 includes, as described above, the baseplate 564. A capping mechanism 590 is supported displaceably on the baseplate 564 to be displaceable towards and away from the printhead 516.The capping mechanism 590 includes an elongate rib 592 arranged on acarrier 593. The carrier is supported by a displacement mechanism 594,which displaces the rib 592 into abutment with the printhead 516 whenthe printhead 516 is inoperative. Conversely, when the printhead 516 isoperational, the displacement mechanism 594 is operable to retract therib 592 out of abutment with the printhead 516.

The printhead sub-assembly 508 includes a printhead support molding 596on which the printhead 516 is mounted. The molding 596, together with aninsert 599 arranged in the molding 596, defines a passage 598 throughwhich the print media 542 passes when an image is to be printed thereon.A groove 700 is defined in the molding 596 through which the cappingmechanism 590 projects when the capping mechanism 590 is in its cappingposition.

An ink feed arrangement 702 is supported by the insert 599 beneath thecap portion 574. The ink feed arrangement 702 comprises a spine portion704 and a casing 706 mounted on the spine portion 704. The spine portion704 and the casing 706, between them, define ink feed galleries 708which are in communication with the ink supply channels 514 in thechassis 510 for feeding ink via passages 710 (FIG. 7) to the printhead516.

An air supply channel 711 (FIG. 8) is defined in the spine portion 704,alongside the printhead 516.

Electrical signals are provided to the printhead 516 via a TAB film 712which is held captive between the insert 599 and the ink feedarrangement 702.

The molding 596 includes an angled wing portion 714. A flexible printedcircuit board (PCB) 716 is supported on and secured to the wing portion714. The flex PCB 716 makes electrical contact with the TAB film 712 bybeing urged into engagement with the TAB film 712 via a rib 718 of theinsert 599. The flex PCB 716 supports busbars 720 thereon. The busbars720 provide power to the printhead 516 and to the other poweredcomponents of the print engine 500. Further, a camera print enginecontrol chip 721 is supported on the flex PCB 716 together with a QAchip (not shown) which authenticates that the cartridge 504 iscompatible and compliant with the print engine 500. For this purpose,the PCB 716 includes contacts 723, which engage contacts 725 in theprint cartridge 504.

As illustrated more clearly in FIG. 7 of the drawings, the printheaditself includes a nozzle guard 722 arranged on a silicon wafer 724. Theink is supplied to a nozzle array (not shown) of the printhead 516 viaan ink supply member 726. The ink supply member 726 communicates withoutlets of the passages 710 of the ink feed arrangement 702 for feedingink to the array of nozzles of the printhead 516, on demand.

In FIG. 10, the air supply path for supplying air to the printhead 516is shown in greater detail. As illustrated, the pump 522 includes animpeller 728 closed off by an end cap 730. The cover molding 520 of thechassis forms a receptacle 732 for the impeller 728. The cover molding520 has the air inlet opening 734 and the air outlet opening 736. Theair inlet opening 734 communicates with the pin 524. The air outletopening 736 feeds air to the air supply channel 518 which, in FIG. 10,is shown as a solid black line. The air fed from the air supply channel518 is blown into the printhead 516 to effect cleaning of the printhead.The air drawn in via the pump 522 is filtered by an air filter 738,which is accommodated in the print cartridge 504. The air filter 738 hasa filter element 740 which may be paper based or made of some othersuitable filtering media. The filter element 740 is housed in acanister, having a base 742 and a lid 744. The lid 744 has an opening746 defined therein. The opening 746 is closed off by a film 748 whichis pierced by the pin 524. The advantage of having the air filter 738 inthe print cartridge 504 is that the air filter 738 is replaced when theprint cartridge 504 is replaced.

It is an advantage of the invention that an air pump 522 is driven bythe stepper motor 530, which also controls feed of the print media tothe printhead 516. In so doing, fewer components are required for theprint engine 500 rendering it more compact. In addition, as the samemotor 530 is used for operating the air pump 522 and for feeding theprint media 542 to the printhead 516, fewer power consuming componentsare included in the print engine 500 rendering it more compact andcheaper to produce.

It is also to be noted that, in order to make the print engine 500 morecompact, the size of the print engine assembly 502 is such that most ofthe components of the assembly 502 are received within a footprint of anend of the print cartridge 504.

In FIG. 11 there is depicted a personal digital assistant having aninternal printer. The digital assistant 901 includes a body section 902housing the main circuitry of the digital assistant including a digitalstorage medium. A display screen 904 is pivotably connected to the bodysection 902 about a hinge joint 905. The screen 904 pivots between aclosed position (FIG. 12) where the screen lies adjacent the bodysection 902 thus allowing safe transport, and an open position (FIG. 11)where the screen 904 is visible to a user.

The body section 902 includes a control panel 906 on an upper surfacethereof that includes all buttons required to operate the functions ofthe digital assistant including the functions of the printer. Using thiscontrol panel, a user can selectively view any stored information andmake any new entries or amendments. The control panel also includes keysallowing the user to selectively print any of the stored information. Aslot 910 in the front edge of the body is used for ejecting printedmedia 911.

The display screen is of a known touch screen type allowing a user tocontrol the digital assistant using a compatible pixel pen (not shown)through which the user selects items on a displayed menu. In additionthe digital assistant may include known pattern recognition softwarethat allows a user to enter information by writing on the screenwhereafter the user's input is analysed and converted into text.

In FIG. 14 there is schematically depicted in block diagram form the keyinternal components of a personal digital assistant having an internalprinter. The printer would typically utilize a monolithic printhead 814which could be the same as described above with reference to FIGS. 1 to10, but could alternatively be another compact printhead capable ofprinting on suitably sized print media. Print data from the memory 909of the digital assistant or a display screen dump 904 is fed to a printengine controller 813 which controls the printhead 814.

A micro-controller 807 associated with the print engine controllercontrols a motor driver 809 which in turn drives a media transportdevice 810. This might be the same as stepper motor 530 describedearlier.

The micro-controller 807 also controls a motor driver 811 which in turncontrols a guillotine motor 812 to sever a printed sheet from anin-built roll of print media after an image is printed. A sheet beingdriven by media transport device 810 is shown at 911 in FIG. 11. Theguillotine might be of the form of cutter wheel 566 described earlier.

When ready, printer control buttons on the control panel can bedepressed to activate the print engine controller to print storedinformation either from memory or as a screen dump from the displayscreen. This would in turn activate the micro-controller 807 to activatethe media transport 810 and guillotine 812.

FIG. 12 shows an internal view of the personal digital assistant in itsclosed position. The printer engine 500 described previously is disposedwithin the body section 902 with the removable print media cartridge 504being disposed in the hinge joint 905 linking the body section 902 withthe display screen 904. Printed media ejected from the print mediapassage 548 of the print engine travels substantially along the innersurface of the bottom panel of the body section 902 and exits thedigital assistant at ejector slot 910. Because the print roll 504 isdisposed within the hinge joint 905, the personal digital assistant ofthe present invention can be made substantially the same size as priorart digital assistants

The body section 902 and hinge 905 include a releasable portion 912pivotably connected through a hinge 913 and secured in a closed positionby a catch 914. Opening of this portion (FIG. 13) allows the inkcontaining print roll cartridge 504 to be removed and replaced. Furtherdetails of a removable print roll cartridge are described in ourco-pending application U.S. Ser. No. 09/607,993 mentioned earlier.

While particular embodiments of this invention have been described, itwill be evident to those skilled in the art that the present inventionmay be embodied in other specific forms without departing from theessential characteristics thereof. The present embodiments and examplesare therefore to be considered in all respects as illustrative and notrestrictive, the scope of the invention being indicated by the appendedclaims rather than the foregoing description, and all changes which comewithin the meaning and range of equivalency of the claims are thereforeintended to be embraced therein. It will further be understood that anyreference herein to known prior art does not, unless the contraryindication appears, constitute an admission that such prior art iscommonly known by those skilled in the art to which the inventionrelates.

1. A print engine for in an inkjet printer, the print engine comprising:a chassis; a print cartridge mounted to the chassis, the print cartridgeincluding a wound length of print media and defining therewithin aplurality of ink reservoirs; a first motor assembly mounted to thechassis, the first motor assembly driving a roller of the printcartridge to transport the print media; a printhead assembly engagedwith the print cartridge, the printhead assembly ejecting ink from thereservoirs onto the transported print media; a cutter assembly forcutting a printed length of print media from the remaining wound length;a second motor assembly mounted to the chassis, the second motorassembly driving the cutter assembly; and a capping mechanismdisplaceable towards and away from the printhead by a displacementmechanism, the capping mechanism including a carrier having an elongaterib positioned to abut with the printhead.
 2. A print engine as claimedin claim 1, wherein the first motor assembly is further configured todrive a pump for drawing air through an air filter in the printcartridge and blowing air over an ink ejection printhead of theprinthead assembly.
 3. A print engine as claimed in claim 2, wherein thefirst motor assembly includes a first gear train for driving the pumpand a second gear train for driving the roller.
 4. A print engine asclaimed in claim 1, wherein the second motor assembly includes a motorcarrying a bevelled gear that meshes with a bevelled gear carried on aworm gear of the cutter assembly.
 5. A print engine as claimed in claim3, wherein the cutter assembly includes a cutter wheel supported on amounting block, the worm gear passing through the mounting block to movethe mounting block linearly along the worm gear.